Delayed action mechanism for snap switches



E. L. SHARP Nov. 4, 1941.

DELAYED ACTION MECHANISM FOR SNAP SWITCHES 2 Shets-Sheet 1 Filed Jan. 2, 1940 fW/IVG L. 571 45 INVENTOR.

Nov. 4, 1941. s 2,261,189

DELAYED ACTION MECHANISM FOR SNAP SWITCHES Filed Jan. 2, 1940 2 Sheets-Sheet 2 6 a 20 E 1i /7 l/ ficfio l 4205 7 7 m. W; Y

L- J T T 1 EWING L. SHAEP,

INVENTOR.

Patented Nov. 4, i941 DELAYED ACTION MECHANISM FOR SNAP SWITCHES Ewing L. Sharp, Los Andes, cum, mmis .Victory Switch Company, Los Angeles, Calif.

Application January 2, 1040, Serial No. 312,011

' 6 Claims. (01. 200-44) The present invention relates to improvements in switches and particularly to a snap action electric switch having an alternate delayed snap action.

The present invention is in certain particulars an improvement on an application for patent for Delayed action switches. Ber. Number 279,137, filed June 14, 1939, which matured in Patent #2,188,685; the present application and the patent just referred to having a common assignee of the entire title to each invention.

One of the important objects of the invention is to provide, in a device of the above character, an electric switch having improved delay action means manually adjustable from an inoperative to an operative position, thereby delaying the opening of the circuit which results from the next operation of the switch for opening the circuit, said delay action means thereupon automatically restoring itself to its inoperative position.

Another important object of the invention is to improve upon the mechanism which causes the delay action.

Still another object of the invention is to provide, in a device of the character stated, an additionally improved toggle acting and push button combination for placing the delay action mechanism into its operative position.

Yet another object of the invention is to provide in a combination snap and delayed action switch additionally improved means for assuring a more positive snap action upon completion of the delayed operation of the switch.

Yet a further object resides in the improvement of the casing whereby certain movable parts in the above referred to co-pending application have been omitted and the construction of other parts simplified and improved upon.

Still further objects, features, and advantages of invention will hereinafter appear.

Referring to the drawings wherein is shown a preferred embodiment of the invention as now reduced in practice.

Fig. '1 is a front elevation of the improved structure assembled within its housing, a portion of the face plate being broken away to show underlying structures. In said figure two wires and a lamp are diagrammatically shown.

Fig. 2 is a vertical mid-section taken on line 2-2 of Fig. 1 showing the toggle lever in the "on" and off positions, a fragment of the conductor conduit is included in this view.

Fig. 3 is an enlarged vertical mid-section showlog the switch on" or in circuit closed position, 55

the dotted lines indicating the position of the parts for snap action and the full line indicating the position of the parts set in readiness for a delayed action.

Fig. 4 is a section similar to Fig. 3 but with the parts in the 011" or open circuit position which they occupy at the completion of the functioning of the delay acting mechanism. The face plate is omitted in Figs. 3 and 4.

Fig. 5 is a view taken on approximately the plane indicated by the line 5-5 of Fig. 3.

Fig. 6 is a vertical section taken on line 6-4 of Fig. 5, the dash-pot cylinder being omitted.

Fig. 7 is a transverse section taken on line 1-1 of Figs. 5 and 6.

F 8. 8 is a transverse section taken on line H of Fig. 5.

Fig. 9 is an enlarged perspective view of the parts which control the delayed action of the switch.

Referring in detail to the drawings, the switch box i has a bottom wall 2 having a circular recess 3 within which is fitted the upper portion of an open-mouthed cup-shaped piston cylinder 4. Said piston cylinder has an external peripheral rib or bead 5 which abuts against the bottom portion of the box i and of its bottom wall 2 when the cup-shaped member 4 is in its mounted position, at which time said member is supported by a set screw 6 which extends through the face strap 1 and with a screwthreaded relation through a downward extension 211 of the aforesaid wall 2, the rib I being thickened at 5a and having a beveled lower face lb, the screw having a tapered end portion which engages said face 5b with a wedging fit to support the member 4 in a secure manner.

A piston head 8 operates within the cylinder 4, said piston having a flattened stem 0 furnished with a longitudinal cam slot I0, said slot being somewhat arcuate and having in the front side of its upper end portion a recess, the lower portion of which forms a seat i l. The upper back portion of stem 9 has a cam portion to which, as the piston descends, is acted upon by an abutment lug Oh that projects internally from the back wall II of the casing. said abutment serving to restore the descending piston stem to its forward position. Said piston 8 is furnished with a gasket shaped as a shallow cup, the peripheral wall of which is sufiiciently flared to allow the piston as a whole to swing sufilciently to operate as hereinafter set forth. The upward travel of the piston stem is arrested by the bumper lug Ila carried by the top wall 12 of the switch box.

- As well shown in plan in Fig. '1 and in ele-.

vation (the face plate being removed) in Fig. 5, the upper part of each side wall ll of the casing has secured to it, by a binding screw II, an L-shaped conductor strip l1, fitted into the ad- Jacent back corner of the casing and a pair of terminal arms I8 which constitute staiecting rise 82 near the upper end oi said stem I. The purpose of giving the upper part of the piston stem this backward swing is to cause a piston depressing pin or finger 86, see Fig. 3, (which is operated by means which will next be described) to be brought from the upper seat H2: into a superjacent relation to the seat H (see Fig. 4) in the upper part of the piston stem.

A swingable yoke Bl (see Fig. 5) has its arms tl 'S' terminal Parts Of a knife blade fi 1 furnished with outwardly directed trunnions 81 Lead wires II are shown to supply current to said parts I! and II. The piston stem is secured to its head at a backward inclination, as shown.

The blade portion 2| of the switch has a deflected free end portion a to cooperate with the pair ll of switch terminals at one side of the casing, and the adjacent portion of a swinging arm 2| which carries said blade 22 likewise cooperates with the other pair oi switch terminals. The body portion of said arm 2i is somewhat J-shaped and at, or a little below, its mid-length is swingably supported by a pivot pin 22 which bridges the slot 22 of a lug 24 formed within I! and are keptin place by the face strap 1 whenthe latter is attached by its screws 1s. Adjacent to one of its trunnions said lever 25 carries conventional stop wings to.

The means for retarding the circuit opening action of the switch includes an elongated button 2 which operates in a guide passage 31 that extends axially through the toggle lever 25 and which has an enlarged inner end portion 314: within the bell portion 25:: of the toggle lever. Within said enlargement 31a is a workably fitted head 40 which is rigidly connected with the button 35 by means of a stem 4|. Said head carries a backward extension 42 having an apertured end portion 43 to which is attached one end of a spiral spring N.

By preference, and as shown, the head ll is a metal plate shaped as a stocky L, the stem ll which unites said head to the button 36 being integral with the head so as to be stamped out therewith. That arm oi. the L which carries the extension 2 also carries at its lower edge a tappet finger H which is at a right angle to the head 40. Said tappet finger 48 is positioned to act upon a slidable engager 48 which, in turn, is positioned to engage the piston stem 9 to swing it back to its original position after said stem has been swung in the reverse direction in the manner hereinafter described.

The slidable engager ll, preferably of a sheet metal character, has a body portion 41, (see Fig. 9), which carries a guide arm, or mounting arm 48, which reciprocates in a guide groove ll provided for it in the interior face of one of the casing side walls i5, said groove having a contacted mouth 49a (Fig. 5) l which keeps said arm 48 in place.

In addition to its mounting arm 48, the engager ll carries an L-shaped push arm I which is positioned to act upon the pistonstem I to swing the upper end of the latter backwardly to the full-line position of Fig. 3, said arm II for this Purpose at times contacting a forwardly prois suitably shaped in its free end portion to have the back end portion of the already mentioned spring 44 held in an operative relation to the yoke in order that said spring may act upon the yoke at times to cause its finger I! to depress the piston in opposition to air contained in the cylinder 4. All portions of the slot II are considerably wider than the diameter of the pin 55, said slot having at about its mid-length a forward swell ilw wherein said pin rests when it is in its lowest position.

Referring again to the J-shaped switch arm 2] which is operable to control th circuit between the switch terminals comprised by the two pairs of contact arms it, said arm 2| is swung in a direction to open the circuit, by reason of being contacted by the yoke II as the latter swings downwardly, urged by spring H, at times freely and at other times in opposition to the retarded piston when the finger II of the said yoke is superimposed upon the seat II in the slotted part of the piston stem.

In such instance the free end portion of said Yoke strikes against the inner side of the hook portion $9 of the arm 2! to swing the arm 21 about its pivot 22 in a direction to open the cir-. cult with a snap action. when the yoke 50 swings upwardly, its free end portion strikes the upper cam face "a of the J-shaped arm and closes the switch with a snap action. When the toggle lever 25 is in the up" position, the sprin H is positioned, by compression, to maintain the yoke 56 in its up" position, to which position it has brought said yoke as a result of the upswinging of said'lever; and when said lever is in the down" position, said spring is positioned, by compression to maintain said yoke in its down" position, to which position it has brought said yoke as a result of the downswinging of said lever.

The piston cylinder or cup 4 has a thickened bottom portion 60 furnished with a screwthreaded central air inlet passage 6|. Said passage is flared at its lower end to cooperate with a screw '2 having a conical head '3. A spongy rubber gasket II is positioned between the head of said screw and the fiared mouth portion of said passage I. This gasket supplies the traction force upon the screw requisite to maintain it in the adjusted position, the amount of air leak through the passage depending upon the amount of compression. The threaded connection between the screw and passage into which it screws forms a sufiiciently loose fit to provide adequate air leakage for the most rapid piston movement desired.

As the stem 8 of the piston is secured to the piston head at the backward inclination to the axis of said head, the back side of said head is assures to pass more readily down its front and back 7 sides.

Speaking briefly of conventional parts not yet mentioned, the face plate I! is of a well-known type and is held in place by screws 10. A conductor conduit II is shown leading into the bottom portion of the casing, but the conventional wiring, which occupies the space shown therefor, is omitted.

Operation The cycle of operation begins with the toggle lever II in the down or "oiff position.- By pushing said lever up, the spring 44, in relation to its point of attachment to the toggle lever, is changed from its extended condition and downwardly inclined position shown in Fig. 4 to an upwardly inclined position, more compressed condition, whence its coils quickly expand causing it to swing the free end of the yoke 56 upwardly till said yoke is arrested in its upward movement by reason of its finger I! striking against the upper end of the slot ll of the piston stem, assuming that said stem is then in its pper position wherein its upper end engages the abutment or stop Ila.

During its upward swing, the free end portion of the yoke, near one of its sides, exerts a cam action upon the face 590 of the arm 2| which carries the switch blade 20, causing the upper end of said arm to swing backwardly and thus move said blade into the circuit completing position.

The upward swin ing of the toggle lever will always cause the operation which has just been described, except, in case the piston Q is in its down position the yoke pin SI will first travel from the mid-length portion of slot ll (see Fig. 4) to a contacting relation to the upper end of said slot. and then, during the final part of its upward movement said yoke pin will carry with it the piston stem until the latter is brought to its uppermost position.

The remaining portion of the cycle of operation is eiieciied by the down throw of the toggle lever 25, which causes the switch blade 2| to be moved to the open circuit portion, either immediately, in case the button 86 is not depressed, or else in a delayed manner, in case the button 38 has previously been depressed to the full line position of Fig. 3. But whether an immediate or delayed circuit opening operation takes place this is efiected by the spring ll being thrown of! center in a downward direction as shown in Fig. 4. If the button 38 has not been depressed before this is done, the yoke pin 55 remains in the body portion of the slot ill of the piston stem and glides freely down said slot without delaying the circuit opening movement of the switch. when, however, the button 36 is depressed before the downward throwing oi the tog le arm, said button moves the stern II and head 40 backwardly and causes the tappet finger Iii carried by said head to slide the engager backwardly, which, in turn, by means of its arm II, to press backwardly upon the upper portion of the piston stem 9 and brings its seat II into a subjacent relation to the yoke pin 55, so that the downward movement of said pin will be opposed and retarded by the dash pot structure of which said piston stem forms a part.

It is to be observed that the recess which forms the seat II in the upper portion of the piston stern slot II is located slightly below the upper end oi said slot. Hence, from the view point of operation, the shallow upper seat Hz results. when the toggle lever II is up the finger ll fits within said seat llx and causes the piston to remain positively in its forward position until it is swimg backwardly in the manner which has been described. Owing to the shallow character of said seat Hz, the presence of pin ll therein offers no objectionable impediment to the backswinging of the piston stem preparatory to its functioning to delay the opening of the circuit.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the subject matter claimed.

What is claimed is:

1. Means for retarding the circuit-opening action of an electric switch, comprising a casing, a dash-pot cylinder in the lower portion of said casing, a piston stem having a head operating in said cylinder, said piston stem having through it a longitudinal slot, there being an upwardly directed seat occupying the lower portion of a forwardly directed extension of said slot, a manually operable toggle lever mounted in said casing in front of said piston stem, a swingable part carrying a finger projecting into said slot to depress said piston stem against the opposition of the contents of said dash-pot cylinder, a spring adjustable by said toggle lever to cause said swingable part to move up or else means carried by the casing to automatically swing said piston stem forwardly thereby releasing said pin from said seat after it has acted upon the latter to depress the piston, and circuit closing and opening means actuated by said swingable part.

2. The subject matter of claim 1 and, said means to swing said piston stem forwardly consisting of a cam lug positioned to be engaged by the descending piston stem.

3. Means for retarding the circuit-opening action of an electric switch comprising a casing, a dash-pot cylinder in the lower portion of said casing, a piston stem having a head operating in said cylinder, said piston stem having an upwardly directed seat formed upon it, a manually operable toggle lever mounted in said casing in front of said piston stem, a swingable part carrying a finger to engage said seat at times to depress said stem against the opposition of the contents of said dash-pot cylinder, a spring adjustable by said toggle lever from one to the other of each of two positions, said sprin in one of said positions causing an upswing of said swingable part and in its other position causing a downswing thereof, means in part carried by said toggle lever and manually movable in relation thereto to swing said piston stem from its normal position to a position wherein its aforesaid seat is brought into a subjacent, relation to said finger preparatory-to the de-r' pression of said piston stem by said linger,

means carried by the casing to automatically swing said piston stem iorwardly during the iinal portion'ot its downward travel under the urge of said finger to release it from said finger, and circuit closing and opening means actuated by said swingable D 4. In combination, a movement retarding means, a casing whereon said means is mounted, a manually operable toggle lever moimted on said casing, a manually slidable member mounted in part axially within said lever and having an inwardly extending portion in an offset relation to the axis or said lever, circuit closing and opening means operatively connected with said oiiset portion oi-said slidable member, and means to retard the circuit opening operation of the switch, the latter means including a compressible and extensible spring which is connected with said oii'set portion of said slidable member, said spring being thrown oil center by each swinging movement or said lever, said lever being swingably supported by pivots which are oflset in relation to the axis of said lever in the same direction and to the same extent as the offset of the aforesaid slidable member.

5. A casing, a dash pot cylinder carried by said casing, a piston stem having a head operating in said cylinder, said stem being swingable a material amount without interfering with the functioning of its head within said cylinder; means to open and close an electric circuit, said aaem'so' uponsaidpistonstemduringtheiinaipartoi I its movement toward said cylinder. 20

handle while said auxiliary mechanism is main-,

tained in an inactive position in either direction said handle is moved to open and close said circuit, and means carried by said handle to put said auxiliary mechanism into position (or op eration by the action 01 said handle in one o! the directional movements. EWING L. SHARP. 

